JPH0452473Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling compressor, particularly to an improvement of a piston device that reciprocates within a cylinder. Conventionally, for air-conditioning compressors, especially compressors that are installed in the engine compartment of a car and constitute a car cooling system, the cylinder liner part where the piston moves back and forth has been made of cast metal in consideration of wear resistance and durability. The casing and cylinder liner were integrally formed by inserting this cast cylinder liner into a casing made of aluminum alloy. However, when using a cast cylinder liner, it is not possible to reduce the weight of the casting beyond a certain level, so the weight of the casing itself including the cylinder liner increases, and it is difficult to manufacture the cast liner and make it from aluminum alloy. It had a defect that increased costs because it required inserting into the casing. For this reason, if the cylinder liner part is made of the aluminum alloy that forms the casing, it will be possible to reduce the weight of the casing and reduce costs, but conventionally, seals in the cylinder chamber and crank chamber are A piston ring was inserted to increase the effectiveness, and since this piston ring was made of high hardness in consideration of contact with the cast liner, it had a defect that made it impossible to use with an aluminum liner.

Furthermore, when an aluminum liner is used in a rocking compressor, even if a resin piston ring is used, the piston 16' placed inside the cylinder will not be able to move accurately as shown in Figure 2. without doing it,
Since the connecting rod 15' connected to the piston 16' has a certain angle with respect to the cylinder center line, the piston 1
A lateral pressure F is generated on the outer surface 18' of the piston 1
6' reciprocates in such a way that the lower end is pressed toward the cylinder liner part 19', so that the side surface of the piston and the cylinder liner part 19'
There was a defect in which the cylinder liner portion 19' was worn out or damaged due to contact between the two cylinders.

The purpose of this invention is to eliminate the above-mentioned defects by forming two grooves on the outer periphery of the piston on the top dead center side and the bottom dead center side. A conical ring-shaped resin piston ring that is larger than the outside diameter of the piston is inserted.
In particular, the conical piston ring on the top dead center side is arranged so as to open toward the top dead center, and the upper edge of the groove on the top dead center side is chamfered in a tapered shape. The contact pressure of the conical piston ring against the cylinder wall can be obtained and the sealing performance can be improved. In addition to the above, the bottom surface of the groove is flat, and the conical piston ring is in contact with the flat groove bottom surface only at the inner edge of the lower end. Since there is a gap between the groove and the piston ring that gradually narrows from above to below, the lubricating oil that has flowed into the space between the groove and the piston ring can be efficiently separated from the refrigerant gas. Furthermore, the piston is prevented from tilting, the defects caused by using aluminum alloy as the cylinder liner are prevented, and the sealing function is improved by the opening direction of the two conical piston rings on the top dead center side and the bottom dead center side. You can make improvements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

Reference numeral 1 denotes a cylindrical casing made of aluminum alloy or the like, and one end thereof is integrally formed with a plurality of cylinders 2 arranged at equal angular intervals on the circumference of the axis. , a cylinder head 6 forming a suction chamber 4 and a discharge chamber 5.
The other end of the cylindrical casing 1 is closed by a front housing 8 which supports a main shaft 7 in the center. A bevel gear 12 is fixed to the center of a planet plate 11 via a thrust bearing 10 on the inclined surface side of a wedge-shaped rotor 9 fixed to the inner end of the main shaft 7, and a cylindrical gear is fixed via a steel ball 13 to the inclined surface side of the wedge-shaped rotor 9. It is made to mesh with the bevel gear 14 fixed to the central hole 1a of the casing 1.

Further, one end of a connecting rod 15 is fitted onto the outer periphery of the planet plate 11, and a piston 16 disposed inside the cylinder 2 is connected to the other end of the connecting rod.

Further, as shown in FIG. 3, two grooves 16a are formed on the outer periphery of the piston 16 on the top dead center side and the bottom dead center side.
16b is formed so that the bottom surface of the groove is flat, and of these grooves 16a and 16b, the outer diameter of the groove 16a in the opening direction as shown in FIG. 5 is larger than the outer diameter of the piston 16 at room temperature. A conical ring-shaped piston ring is inserted in a predetermined manner as shown in FIG. 3a. That is, the conical ring-shaped piston ring 17a has the groove 16a only at the inner edge of the lower end.
so that it is in contact with the flat bottom of the groove.

In addition, with reference to FIG. 5, the inner diameter of the conical ring-shaped piston ring is formed to be smaller than the diameter of the bottom of the groove of the piston before it is installed in the groove, and the diameter is forcibly reduced. It is expanded and inserted into the groove of the piston. In this way, the small diameter end side of the ring comes into close contact with the bottom surface of the groove. Of course, the conical piston ring is in the state before being installed on the piston.
It may be formed in a washer shape with an inner diameter smaller than the diameter of the groove bottom surface and an outer diameter larger than the outer diameter of the piston.When installing the piston, by enlarging the inner diameter and installing it, it is possible to form a conical ring shape in the groove. It fits in.

Also, when the piston 16 reciprocates within the cylinder 2, one of the piston rings 17a and 17b inserted into the two upper and lower grooves 16a and 16b on the outer surface of the piston 16 as shown in FIG. The piston ring 17a arranged at the upper end of the piston 16 has a sealing function to prevent refrigerant from leaking from the inside of the cylinder 2 into the crank chamber 20. The chamfer 21 formed on the upper edge of the ring groove 16a allows the piston ring 17a to follow the gas pressure when it is compressed, and the pressing force against the cylinder 19 works efficiently, thereby significantly improving the sealing ability.

Piston ring 1 arranged at the lower end of piston 16
7b has a function of reducing the inclination of the piston due to the side pressure F generated on the outer surface 18 of the piston 16 due to the reciprocating movement of the piston 16, and a sealing function of preventing refrigerant leakage, contributing to improvement of sealing ability. There is.

Further explaining with reference to FIG. 6, the piston 16
Piston rings 17a, 17 arranged at the upper and lower ends of
Cylinder 2 internal pressure Pa and crank chamber 20 internal pressure between b
An intermediate pressure Pb of Pc occurs, and in the compression stroke Pa
The overall sealing ability is further improved by improving the sealing function with the two-stage seal with the relationship >Pb>Pc.

Furthermore, since sealing with piston rings 17a and 17b arranged at the upper and lower ends of the piston 16 provides a good two-stage seal, there is a concern that the amount of lubricating oil contained in the refrigerant returned to the crank chamber 20 will decrease. However, this can be resolved by the following mechanism.

That is, in the piston of the cooling compressor of this embodiment, the bottom surface of the groove bottom 22a is flat, and the conical ring-shaped piston ring 17a is in contact with the flat groove bottom surface only at the inner edge of the lower end. Since there is a gap between the conical piston ring 17a and the conical piston ring 17a, which gradually narrows from above to below, the ability to separate lubricating oil from the refrigerant is significantly improved during the compression process, and the lubricating oil is separated from the groove bottom 22a. It accumulates in the gap between the conical piston ring 17a and the space above it (space A). The lubricating oil is pushed out into the space between the conical piston rings 17a and 17b by the gas pressure of the compression process and fills the space, and new oil is separated and accumulated in the space A. Furthermore, since the bottom dead center direction of the piston ring 17b arranged at the lower end of the piston 16 is opened outward, the lubricating oil accumulated between the piston rings 17a and 17b is released during the compression stroke due to the wedge effect. It is easily pushed out to the cylinder wall surface under the piston ring 17b by gas pressure. During the suction stroke, the lubricating oil is transferred to the lower end edge of the piston ring 17b and the crank chamber 20.
Scraped inside.

As a further application, in Fig. 4, the piston 1
The top dead center direction of the piston ring 17b disposed at the lower end of the piston ring 17b is opened outward. In this case, the lubricating oil accumulated between the piston rings 17a and 17b is caused by the gas pressure of the compression stroke, as shown in FIG.
Similar to the flow of lubricating oil through the inside, it passes through the inside of the piston ring 17b and is pushed out to the cylinder wall surface below the piston ring 17b. The lubricating oil is then scraped off into the crank chamber 20 by the upper edge of the piston ring 17b during the suction stroke.

In this way, during the compression stroke, the piston ring 17a
The oil in the refrigerant is separated into the space A above the
The oil filled between the piston rings 17a and 17b is pushed out below the piston ring 17b,
The lubricating oil contained in the refrigerant is removed from the crank chamber 2 by an efficient mechanism that scrapes it off with the outer edge of the piston ring 17b during the suction stroke.
The amount returned to zero is ensured sufficiently. In this way, an appropriate amount of lubricating oil can be recirculated into the crank chamber 20 to improve the lubrication ability.

As described above, the present invention has two grooves 16a and 16 on the outer circumference of the piston 16 on the top dead center side and the bottom dead center side.
A conical ring-shaped resin piston ring whose outer diameter is larger than the outer diameter of the piston 16 at room temperature is inserted into this groove, and the piston 1
The use of aluminum alloy for the cylinder liner eliminates contact between the outer surface 18 of the cylinder 6 and the cylinder liner part 19, and prevents wear of the cylinder liner part 19 and seizure caused by this, especially in rocking compressors. This has the excellent effect of reducing the weight of the cooling compressor body.

In addition, when conventional cast liners were used, it was necessary to go through the process of manufacturing the cast liner and inserting the cast liner into a casing made of aluminum alloy, which was expensive. If the cylinder liner is formed from the aluminum alloy of the present invention, it can be molded integrally with the cylindrical casing, which has the effect of reducing costs.

In addition, the top dead center direction of the piston ring 17a is outward-opening, and the chamfer 21 on the upper edge of the ring groove 16a of the piston allows the piston ring 17a to follow the gas pressure well when compressed, and to The pressing force acts efficiently, two piston rings 17a and 17b are used, and an intermediate pressure between the cylinder internal pressure and crank chamber pressure is generated during compression, creating a two-stage seal with little leakage. This has the effect of significantly improving performance.

Further, the bottom surface of the groove bottom 22a is flat, and the conical ring-shaped piston ring 17a is in contact with the flat groove bottom surface only at the inner edge of the lower end, so that the piston ring 1
There is a gap between the groove bottom 22a and the groove bottom 22a that gradually narrows from above to below, thereby significantly improving the ability to separate lubricating oil from the refrigerant. Further, the lubricating oil separated from the refrigerant gas returns to the crankcase due to the lubricating oil holding effect between the piston rings 17a and 17b and the scraping effect due to the inclination of the piston ring on the bottom dead center side. That is, the lubricating oil that has accumulated between the piston ring on the top dead center side and the piston ring on the bottom dead center side is caused by the gas pressure of the compression process to cause the lubricating oil to leak between the piston ring 17b on the bottom dead center side and the wall surface of the cylinder 19. (see Figure 6) or the piston ring 1 on the bottom dead center side
7b and the piston groove bottom 22b (see Figure 7)
During the suction stroke, the piston ring 17b is scraped into the crank chamber 20 by the lower edge (see FIG. 6) or the upper edge (see FIG. 7) of the piston ring 17b on the bottom dead center side. In this way, in the present invention, since the piston ring on the top dead center side has the chamfer described above, not only the refrigerant gas sealing effect is dramatically improved, but also the refrigerant gas is gradually narrowed down as described above. Because it has voids,
Lubricating oil in refrigerant gas can be efficiently separated. Therefore, this separated lubricating oil passes through the piston ring on the bottom dead center side and returns to the crankcase, thereby contributing to the lubrication of the sliding parts in the crankcase, which is a remarkable effect unique to the present invention. have.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a cooling compressor to which the present invention is applied, Fig. 2 is a sectional view showing an example of a conventional piston-cylinder, and Fig. 3a is a piston showing an embodiment of the present invention. - A sectional view showing the configuration of the cylinder, FIG. 3b is an enlarged view of part A in a, FIG. 4 is a view showing another embodiment of the present invention, and a is a sectional view showing the piston-cylinder configuration; b is an enlarged view of part A in a, FIG. 5 is a sectional view showing the shape of the piston ring, FIG. 6 is a sectional view of the main part for explaining the operation of the embodiment shown in FIG. 3, and FIG. FIG. 4 is a sectional view of a main part for explaining the operation of the embodiment shown in FIG. 4;

Claims (1)

[Claims for Utility Model Registration] 1. Grooves are formed near the top dead center end and the bottom dead center end on the outer circumferential surface of the piston that reciprocates within the cylinder 2, and both grooves have an outer diameter that corresponds to A conical ring-shaped resin piston ring larger than the outer diameter of the piston was inserted, the bottom surface of the groove was flat, and the upper edge of the groove on the top dead center side was chamfered into a tapered shape. , the conical ring-shaped piston ring on the top dead center side is arranged to open outward toward the top dead center, and the conical ring-shaped piston ring contacts the flat groove bottom surface only at the inner edge of the lower end. A piston for a cooling compressor characterized by: 2. The piston of the cooling compressor set forth in Claim 1 of the Utility Model Registration Claim is characterized in that the conical piston ring on the bottom dead center side is arranged so as to open outward toward the bottom dead center. Cooling compressor piston. 3. In the piston of the cooling compressor according to claim 1 of the utility model registration claim, the conical piston ring on the bottom dead center side is arranged so as to open outward toward the top dead center. A piston for a cooling compressor.